Freelance Senior OR Junior Full Stack Developer – React / Next.js / Node.js – Barcelona

Freelance Senior OR Junior Full Stack Developer – React / Next.js / Node.js – Barcelona
Asegúrese de leer detenidamente la información sobre esta oportunidad antes de presentar su candidatura.

You will collaborate closely with the Tech Lead, Product Owner, UX Designer, and Data team to design, develop, and deliver high-quality features within an agile environment.

Responsibilities

• 
  
• Develop and maintain complex, data-heavy user interfaces using React and Next.js
  
• Build and optimise reusable components and contribute to the internal UI library
  
• Design and integrate REST APIs and WebSocket endpoints
  
• Ensure code quality through clean architecture and best practices
  
• Write unit and integration tests (Jest / Testing Library)
  
• Collaborate with Product, UX, and Data to deliver features end-to-end
  
• Participate in architecture discussions and decision-making
  
• Troubleshoot and resolve issues across the stack
  
• Contribute to CI/CD processes and development workflow improvements
  
• Maintain documentation on Confluence
  

Required Qualifications

• 
  
• 3-5+ years of experience as a Full Stack or Front-End Engineer
  
• Strong hands-on experience with React.js and Next.js
  
• Experience building and consuming REST APIs
  
• Good understanding of backend technologies (Node.js required; Python/FastAPI is a plus)
  
• Experience with component libraries , design systems, or shared UI components
  
• Familiarity with modern testing frameworks (Jest, Testing Library)
  
• Good understanding of performance, security, and scalability principles
  
• Comfortable working in cross-functional agile teams
  
• Strong communication skills in English
  

Nice to Have

• 
  
• Experience with container technologies (Docker , AWS ECR/EKS, OpenShift)
  
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• Experience with CI/CD pipelines
  
• Knowledge of SonarQube, Checkmarx, or similar code quality tools
  
• Experience in healthcare, pharma, or other regulated environments
  

What We Offer

• 
  
• Full-time freelance mission
  
• 3-month contract, renewable depending on performance and roadmap
  
• Hybrid environment from Barcelona
  

Seniority level

Mid-Senior level

Employment type

Full-time

Job function

Information Technology

Industries

Pharmaceutical Manufacturing

Barcelona, Catalonia, Spain

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